The invention relates to a lamp of the type having a protective sleeve surrounding a light source, in particular a metal halide arc tube having a pair of opposed leads. The sleeve is supported by a metal frame comprising a pair of metal frame members which also supply current to the leads.
Protective sleeves of quartz or other transparent material able to withstand operating temperatures are commonly utilized around metal halide arc tubes, also known as high intensity discharge or HID arc tubes, in order to provide protection against non-passive failure during lamp operation. These sleeves act to slow or stop fast moving arc tube fragments and prevent the rupture of the outer lamp envelope. These sleeves may also provide other functions including, but not limited to, reduction of the UV output of the lamp. Typical examples of such lamps may be found in U.S. Pat. No. 6,157,131 issued Dec. 5, 2000 and U.S. Pat. No. 6,329,742 issued Dec. 11, 2001, both assigned to the assignee in this application. These patents are addressed primarily to unique mounting characteristics for particular lamp designs which position a sleeve over the arc tube of the lamp for the purpose of containment protection if the tube ruptures or is ruptured. Such ceramic discharge metal halide lamps using a sleeve as a means of protection and exhibiting a color temperature of about 3000K, usually exhibit a color rendering index (CRI) in the low 80's.
There is a continued need in the art for protected ceramic discharge metal halide lamps that exhibit an improved color rendering index, and in particular for protected ceramic discharge metal halide lamps that exhibit a color temperature of about 3000K and an improved color rendering index.